Clutch



April 23, 1946.

H. SQHNEIDER CLUTCH Filed April 27, 1942 V 2 Sheets-Sheet 2 PatentedApr. 1946 CLUTCH Heinrich Schneider, Hamilton, Ohio, allignor toSchneider Brothers Company, a oopartnership composed of HeinrichSchneider and Viva K Schneider,

Hamilton.

Ohio, and Adolf G.

Schneider and Erna Schneider, Mnncie, 1nd.

Application April 27, 1942, Serial No. 440,030

11 Claims.

Thisapplication is a continuation in part of my copending applicationSerial No. 344,300, filed July 8, 1940. i 7

speed multiple friction disk clutcheaby providing for positive locationof the pistons in disengaged position, providing plenty of clearanceThis invention relates to clutches and is more particularly concernedwith improvements in hydraulically or fluid pressure operated pistontype clutches, which while suitable for use for various. purposes areespecially designed and adapted for use in combination with turbinedrives, more particularly turbine ring converters. They may be used fortransmitting extremely high torque with the application of high oilpressure on the pistons to connect and disconnect shafts, particularlyin industrial applications.

The principal object of my invention is to provide a clutch of small andcompact construction suitable for high power duty in the transmission oftorque. When used in combination with turbine drives, the clutch can befurther reduced in size by using very high oil pressure for engagementof the small friction areas of the clutch, inasmuch as the clutch iscalled upon to synchronize, in this combination, only a floating rotorof small inertia and to transmit high torque after the engagement of theclutch.

A salient feature of the clutch of my inven-v tion is its symmetricaldesign, whereby thrust is balanced internally so that thrust bearingscan be eliminated, or at least substantially reduced in size.

between the friction surfaces, and using cooling oil for controlledcooling of the friction surfaces in idling.

Another object consists in the reduction of the weight of the clutch.particularly in the thickness of the side plates of the drum, andlimiting their deformation by the use of thrust rings rigidly secured tothe shaft; Sufficient clearance between the thrust rings and the sideplates in disengaged position is provided, so that duringsynchronization of the shaft and the drum the thrust rings are notengaged and only by further deformation of the side plates under highoil pressure the clearance is taken up and the thrust Another objectconsists in the provision of a clutch of the kind mentioned in which thefriction drive surfaces are made up of a multiplicity of small frictionsurfaces "on interfltting vshaped teeth and grooves on the relativelyrotatable parts, all arranged to be well lubricated. cooled, and cleanedby the circulation of oil over the surfaces. In accordance with myinvention, the piston heads in which the teeth are out are made ofsofter material than the side plates of the drum in which the V-groovesare provided, so that there is little or no wear on the side plates andvirtually all of the wear is takenon rings come into action.

Still another object consistsin the provision of a clutch of the kindmentioned, especially designed and constructed to allow the arrangementof the clutch inside standard gear sizes, whereby it is possible tobuild transmissions consisting of hydraulic turbine drives incombination with multiple gear sets and reverse gears of small dimensionand light weight for use in Diesel locomotives, army tanks, trucks,busses, and automobiles.

The foregoing and other objects of the invention are set forth in thefollowing description, in which reference is made to the accompanyingdrawings. wherein- Figure 1 is a longitudinal section through a hydraulic transmission embo ying piston clutches made in accordance withmy invention;

Fig. 2 is a cross-section of one of the two gear sets shown in Fig. 1';V

Fig. 3 is a sectional detail on a larger scale,

showing a piston clutch construction including thrust rings, and

Fig. 4 is a section similar to Fig. 3 showing another construction, inwhich the pistons have a the pistons. The use of a multiplicity ofsmallpistons as contemplated by my invention makes practical the use ofhigh oil pressure which can be sealed effectively by piston rings, andit en-' idling friction, which is still a problem with high 6 retractingspring connected thereto and the drum has provision for circulating oilbetween the friction drive surfaces. q

Similar reference numerals are applied to corresponding parts throughoutthe views.

Referring first to Figs; '1 and 2, ii designates the primary or shaft,such as the crank shaft, of an engine or other prime mover and if is theimpeller'of a hydrauli torque converter T turning with the shaft II. Thetorque converter includes a turbine wheel; i3 and stationarreactionmember ii. The turbine wheel It drives the secondary shaft itwhich extends from the torque 24 provided on the projecting end thereoffor connection with the device to be driven, whether it be a vehicle orindustrial machinery. A hollow clutch drum 25 is freely rotatable withrespect to the shaft I on bearings 26 and has a ring gear 21 fixed onits peripher meshing with another gear 28 keyed on the countershaft 2|.A hub 28 suitably secured to the shaft It has a plurality oflongitudinal bores 30 provided therein in equally circumferentiallyspaced relation, all at the same radial distance from the axis of theshaft I5 and parallel thereto. Two oppositely facing pistons 3| areslidable in each of these bores and are adapted to be moved outwardlyaway from one another under oil pressure, oil being admissible throughpassages 32 to the bores 30 under high pressure to force the pistons 3|apart, and 011 being admissible through other passages 33 under a lowerpressure to the inside of the drum 25 to return the pistons when thehigh pressure is relieved. The pistons 3| have a number of concentricarcuate ridges 34 provided on their head ends, struck with the axis ofthe shaft I5 as a center and adapted to fit in corresponding circulargrooves 35 provided on the side walls inside the drum 25, whereby thepistons 3| when forced outwardly under oil pressure engage their ridgesin the grooves in the drum 25 to clutch the drum and turn it with theshaft I5. On the other hand when the oil pressure in the bores 30 isrelieved and oil under pressure is supplied through the passages 33 toforce the pistons 3 I inwardly to retracted positions, the drum 25 willbe accordingly released from driving connection with the shaft The gear36 is keyed to the shaft I5 and meshes with another gear 31 fixed on theperiphery of another clutch drum 38, similar to the drum 25 an mountedto turn freely with respect to the countershaft 2| on bearings 26. A hub39 similar by the countershaft 2|, will stand still. If high pressure011 is supplied through passages 32 to force the pistons 3| outwardlyinto clutching engagement with the drum 25, the countershaft 2| will beturned at a speed above that of the shaft I5 determined by the speedratio of the gears 21 and 28. If, on the other hand, the high oilpressure is relieved in passages 32 so as to allow the return of thepistons 3| under low pressure from the oil delivered through passages38, the gears 21 and 28 are disconnected from driving relation with theshaft I5, and if thereafter oil under high pressure is delivered throughpassages 42 to move the pistons 4| into clutching engagement with thedrum 38, the countershaft 2| will then be turned at a lower speed thanthe shaft I5 determined by the speed ratio of the gears 38 and 31. Inother words, either of two different speed ratios may be selected. Theimportant advantages of the invention will be apparent if one takes intoconsideration the fact that the countershaft 2| in the driving of a vetothe hub 29 is suitably secured to the countershaft 2| to turn therewithand has bores 60, similar to the bores 30 previously mentioned, withoppositely facing pistons 4| arranged to cooperate with the walls of thedrum 38 similarly as in the hydraulic clutch previously described. Itwill be noticed that the pistons 6| are shown in disengaged relation tothe drum 38, whereas the pistons 3| are shown in engaged relation to thedrum 25. Passages 42 suppl oil under high pressure to the bores 40 toforce the pistons outwardly, whereas oil under low pressure is suppliedthrough passages 23 to theinside of the drum 38 to return the pistonswhen the high pressure is relieved.

In operation, assuming that the high pressure passages 32 and 42 are atatmospheric pressure, whereas the passages 33 and 53 are continuouslyconnected to the low pressure oil supply, thus keeping the pistons 3|and ll in retracted relation to the drums 25 and 38, respectively, noconnection exists between the gear 27 and shaft I5 on the one hand orthe gear 31 and the shaft 2| on the other hand. Hence, if the impellerI2 of the torque converter T is driven, the turbine wheel I3 will rotateat its maximum speed and the gear pair 363I, the motion of which isdetermined by the sh: ft I5, will also turn, the gear pair 21-28, themotion of which is determined hicle such as a locomotive is connected at24 to heavy moving parts having large mass and large moment of inertia,and if one also takes into consideration the fact that the impeller I2of the torque converter T is driven by a prime mover of alsocomparatively heavy mass and large moment of inertia. Two of the threeindependently movable systems cannot change their speeds suddenlywithout the application of a large force. The first of these systems isthe engine whose shaft is shown at H and the attached pump impeller I2of the torque converter, and the second of these systems comprises thedriven masses of the main machinery (such as a locomotive) together withthe countershaft 2| and attached hub 39 and gear pair 21-28. In theconventional clutch design, synchronization and connection must beestablished between these two systems directly when a clutch is engaged,and, due to the heavy masses of these systems, even a slight speedchange in either system during the process of engagement necessitatesdissipating a comparatively large amount of energy which mustnecessarily be lost as heat energy in the friction surfaces of theclutch. With the present invention, that highly undesirable condition isavoided because there is provided between the two masses a floatingrotor of comparatively small mass and moment of inertia forming thethird independently movable system. In Fig. 1, this third systemcomprises the turbine wheel l3 together with the secondary shaft I5 andthe gear pair 36--3l. When a clutch engagement occurs with the presentgear box, it will establish a speed relation between the secondary shaftI5 and the countershaft 2| difi'erent from the one existing before theengagement. The forces necessary to bring about this change in speedwill substantially be determined by the speed change of the secondaryshaft I5 alone, the reason for this being that the masses attached tothe countershaft 2| have a substantially larger moment of inertia thanthe masses attached to the shaft I5, forming the floating rotor, and Ihave found that in any kind of turbo-hydraulic machinery there is noappreciable resistance to a quick change in speed of one of the rotatingmembers beyond the moment of inertia of the rotating wheels, the onlyadditional resistance involved being the inertia resistance of the fluidparticles, which is generally much smaller than the inertia resistanceof the wheel ascaaoc changing its speed. As a result, whereas with otherdesigns there must be a comparatively slow engagement in order not toimpose any undue or even destructive stresses on the machinery, with thepresent design I have found it entirely feasible and practical to employpiston type clutches of the kind illustrated at 3| and 4|, havingconsiderably smaller frictional engaging surfaces but higher engagingpressures, these clutches being designed primarily for the function oftransmitting power and only to a negligible extent as slip and heateonsumingelements. The slip between the large masses of the prime moveron the one hand and the driven machinery on the other is absorbed in thetorque converter T. I have found by extensive tests that with myinvention, using these piston type clutches, engaging pressures severaltimes that used in ordinary friction clutches of the disk type, andfriction surfaces having an area afraction of what was used in theordinary friction clutches of the disk type can successfully be used incombination with a turbo ring drive. I have, for example, providedpistons having engaging surfacesof such small areas in relation to thefluid pressure applied, that the friction surface pressure in the clutchis upwards of 100 pounds per square inch. That makes it possible to useclutches of unusually small dimensions so that space, cost, and weightare greatly reduced. The

smallness of the clutch units furthermore re-- duces the surface speedof the engaging faces, thus further reducing the danger of overheating,distortion, and scoring. Moreover, there is nothing to prevent the useof these clutches in conjunction with very high powered prime movers,and, in accordance with my invention, selective, multiple speed gearboxes can now be made for several thousand horse-power, in combinationwith a turbo-hydraulic drive. The quickness with which one may shiftfrom one speed ratio to another with the present invention is also quitean advantage as compared with the performance of other transmissionsavailable and insures an almost uninterrupted power flow.

The material of the pistons 3| and 4|, in which the arcuate ridges orteeth 34 are'cut, is preferably softer than the material of the drums 25and 28 in which the mating annular grooves 35 are provided. Thus thepistons, or at least the head portions thereof, may be made of bronze orany composition material like those commonly used for clutch facings orbrake linings, and the drums, or at least the side plates thereof, maybe made of harder'material such as steel, preferably hardened. Therewill, then, be little orno wear on the drums and virtually all thewearwill be taken by the pistons. The included angle of the V-grooves 35should be preferably between and 30. This construction, it will beunderstood, applies not only to the piston clutches disclosed in Figs. 1and 2 but also to those illustrated in the other figures.

Referring now to Fig. 3, the piston-clutch therein shown is similar tothat disclosed in Fig.

, axial movement with respect to the shaft and Q Q engaged by theflanged end of bushings 94 tuming with the drum. A hub 99 keyed,splined, or otherwise secured, to the shaft 9| has bores 99 providedtherein parallel to the shaft axis and in equally circumferentiallyspaced relation and all atthe same radius from the shaft axis, eachcontaining a pair of pistons 91, which, like the pistons 9| and 9| inFig. 1, have arcuate teeth or ridges 34 on their head ends arranged toengage in circular grooves 35 provided on the inner faces of the sideplates I1 and I9. Piston rings 98 in the pistons minimize leakage of oilpast the pistons in either direction, and a split ring 99 entered in anannular groove 99 at the middle of each of the bores 99 limits themovement of the tinuously connected to the low pressure 011 supply willdeliver oil to the inside of the drum and keep the pistons 91 inretracted position so that there is no driving connection between thegear 18 and shaft 8|. Thrust rings 99 limit deformation of the sideplates 11 and 19 when oil pressure is supplied through the passages 9|to force the pistons 81 outwardly into clutching engagement with thedrum. There is normally appreciable clearance between the thrust ringsand the side plates when the clutch is disengaged. In the initialengagement of the clutch during synchronization of the shaft Bi and thedrum thrust rings will preferably not beengaged, but aftersynchronization, upon further deformation of the side plates under highoil pressure admitted through the passages 9|, the clearance will betaken up and the thrust rings 99 will come into action and limitthe'deformaticn.

In the clutch shown in Fig. 4, the ring gear 19' is mounted on sideplates 11' and 18', forming a drum around the hub that turns with theshaft 8|, similarly as in the structure of Fig. 3. However, in thisclutch, it will be noticed that I have provided radial holes 93 in thering gear, so that oil delivered to the inside of the drum through theradial passages 92' in the shaft 9| will serve not only to lubricate andcool needle bearings 94 provided for anti-friction support of the drumon the shaft but will also wash out through the drain holes 93 chips anddust from the inter-engaging V-shaped' and 99, are hardened steel rings,and at 91 are indicated bronze thrust rings. A coiled tension spring 98is provided for retracting each pair of pistons. on each end of thespring a steel ring 99 is screwed over the spring by means of internalgrooves I99 in the rings, and the rings are then brazed to the springand threaded into the pistons, as indicated at |9|. To'assemble thepistons in the bores, one piston in which the spring is tightly screwedis inserted from one side and the other piston is'inserted from theother side and threaded onto the spring ring, using two wrenches, one oneach of the pistons fitting between the teeth thereof. i

The operation of this piston clutch is generally similar to that shownin Fig. 3, except that the springs 88 insure prompt disengagement of theclutch when the high pressure 011 passages 9! are at atmosphericpressure. The springs retract the pistons 81' into engagement with theopposite sides of the rings 89, and grooves 81b in the pistons maintaincommunication between the bores 86' and the high pressure oil passages9|. When oil is delivered under high pressure through the passages 9|,the pistons 81' are moved outwardly against the action of the springs 98for engagement of the clutch. The oildeiivered continuously through thepassages 98', keeps the parts well lubricated and also insures clearingout of chips and dust through the drain holes 93.

It is believed the foregoing description conveys a good understanding ofthe objects and advan tages of my invention. The appended claims havebeen drawn to cover all legitimate modifications and adaptations.

I claim:

1. A clutch for use between a driving member and a driven member,comprising a hub turning with one of said members having bores providedtherein substantially parallel to the axis of rota-,

tion, a pair of oppositely facing pistons in each bore, means foradmitting fluid pressure to the bores between the pistons to force themoutwardly for engagement of the clutch, and a drum turning with theother of said first mentioned members enclosing the hub and providingwalls on opposite sides of the hub for frictional driving engagementwith the head ends of the pistons, the walls having a plurality ofconcentric annular ridges and grooves provided therein struck with theaxis of the hub as a center, and the head ends of said pistons havingmating, concentric, arcuate grooves and ridges for interflttingfrictional engagement of the head ends of the pistons with said walls inthe engagement of the clutch.

2. A clutch for use between a driving member and a driven member,comprising a, hub tuming with one of said members having bores providedtherein substantially parallel to the axis of rotation, a pair ofoppositely facing pistons in each bore, means for admitting fluidpressure to the bores between the pistons to force them outwardly forengagement of the clutch, and a drum turning with the other of saidfirst mentioned members enclosing the hub and providing walls onopposite sides of the hub for frictional driving engagement with thehead ends of the pistons, the walls having a plurality of concentric,tapered, annular ridges and grooves provided therein struck with theaxis of the hub as a center, and the head ends of said pistons havingmatching, concentric, arcuate grooves and ridges for interfittingwedging frictional engagement of the head ends of the pistons with saidwalls in the engagement of the clutch.

3-. A clutch for use between a driving member and a driven member,comprising a hub tuming with one of said members having bores providedtherein substantially parallel to the axis of rotation, a. pair ofoppositely facing pistons in each bore, means for admitting fluidpressure to the bores between the pistons to force them outwardly forengagement of the clutch, and a drum turning with the other of saidfirst mentioned members enclosing the hub and providing surfaces on theinside thereof on opposite sides of the hub for frictional drivingengagement with the head ends of the pistons. the pistons having headportions of softer material in relation to the hardness of the materialin those portions of the drum engaged by said pistons.

4. A clutch for use between a driving member and a driven member,comprising a hub turning with one of said members having bores providedtherein substantially parallel to the axis of rotation, a. pair ofoppositely facing pistons in each bore, means for admitting fluidpressure to the bores between the pistons to force them outwardly forengagement of the clutch, a drum turning with the other of said firstmentioned members enclosing the hub, interengageable friction meansprovided between said drum and said pistons adapted to be held indriving engagement under thrust of said pistons, whereby to transmitdrive between said driving and driven members, the aforesaid fluidpressure means including a fluid passage in the hub communicating withthe approximate mid-point of each bore, each of said bores having anannular groove provided therein at the mid-point narrower than thepassage, and a split ring entered in the groove for limiting inwardmovement of the pistons.

5. A clutch for use between a driving member and a driven member,comprising a hub turning with one of said members having bores providedtherein substantially parallel to the axis of rotation, a pair ofoppositely facing pistons in each bore, means for admitting fluidpressure to the bores between the pistons to force them outwardly forengagement of the clutch, a drum turning with the other of said firstmentioned members enclosing the hub, interengageable friction meansprovided between said drum and said pistons adapted to be held indriving engagement under thrust of said pistons, whereby to transmitdrive between said drivingand driven members,

and a spring means interconnecting the pistons of each pair tending tourge the pistons inwardly toward each other.

6. A clutch for drivingly connecting a gear and shaft, comprising a hubturning with the shaft having bores provided therein substantiallyparallel to the axis of rotation, a pair of oppositely facing pistons ineach bore, means for admitting fluid pressure to the bores between thepistons to force them outwardly for engagement of the clutch, the gearbeing a ring gear surrounding said hub, and a pair of side platesrotatable relative to the shaft and turning with said gear and disposedon opposite sides of said hub to form an enclosing drum for said hub,said side plates providing surfaces on the inner side thereof onopposite sides of the hub for frictional driving engagementwith the headends of the pistons.

7. A clutch for drivingly connecting a gear and shaft,'comprising a hubturning with the shaft having bores provided therein substantiallyparallel to, the axis of rotation, a pair of oppositely facing pistonsin each bore, means for admitting fiuid pressure to the bores betweenthe pistons to force them outwardly for engagement of the the drum at apoint near the axis of rotation opposite sides of the hub which providefriction and draining the fluid from the drum at the periphery thereof.

8. A clutch adapted for use in a hydraulic turbo ring drive fortransmitting drive from a driving element to a driven element,comprising a hub member turning with one of said elements, a an drummember turning with the other of said elements and enclosing the hubmember, pistons movable in bores provided in one of said members andarranged to have frictional driving engagement with surfaces provided onthe other of said members, and means for admitting fluid under highpressure to the bores to cause engagement of said pistons with saidsurfaces,

whereby substantially no slip energy in the transmission of power isabsorbed in said clutch.

9. A clutch as set forth in claim 8, wherein the pistons have engagingsurfaces of; such small area in relation to the fluid pressure applied,whereby the friction surface pressure in the clutch is upwards of onehundred pounds per square inch.

10. A clutch for use between a driving member and a driven member,comprising a hub turning with one of said members having bores providedtherein substantially parallel to the axis of rotation, a pair ofoppositely facing pistons in each bore, means for admitting fluidpressure to the bores between the pistons to force them outwardly forengagement of the clutch, a drum turning with the other of said firstmentioned members enclosing the hub and including side plates onsurfaces on the inner sides thereof for frictional driving engagementwith the head ends of the pistons, said side plates being distortableoutwardly with respect to the hub under pressure of said pistons, andthrust rings mounted on the first mentioned member on opposite sides ofthe hub in spaced relation to the side plates and arranged to haveengagement with the outer sides of said side plates to limit outwarddistortion thereof.

11. A clutch for use between a driving mem each bore, means foradmitting fluid-pressure to.

the bores between the pistons to force them outwardly for engagement ofthe clutch, a-drum turning with the other of said first mentionedmembers enclosing the hub and including side plates on opposite sides ofthe hub which provide friction surfaces on the inner sides thereof forfrictional driving engagement with the head ends of the pistons, saidside plates being distortable outwardly with respect to the hub underpressure of said pistons, and means for taking up the thrust, arrangedon the first mentioned member on opposite sides of the hub in spacedrelation to the side plates and arranged to have engagement with saidside plates to limit outward distortion thereof.

HEINRICH SCHNEIDER.

